80 lines
2.6 KiB
YAML
80 lines
2.6 KiB
YAML
# Copyright (c) 2019, STMicroelectronics
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# SPDX-License-Identifier: Apache-2.0
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description: |
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STM32 DMAMUX controller
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The STM32 DMAMUX is a direct memory access multiplexer
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capable of supporting independent DMA channels.
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DMAMUX clients connected to the STM32 DMA ultiplexer must use a two-cell specifier
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for each dmamux channel: a phandle to the DMA multiplexer plus the following 2 integer cells:
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1. channel: the mux channel from 0 to <dma-channels> - 1
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2. slot: the request line Multiplexer ID
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3. channel-config: A 32bit mask specifying the DMA channel configuration
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which is device dependent:
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-bit 6-7 : Direction (see dma.h)
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0x0: MEM to MEM
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0x1: MEM to PERIPH
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0x2: PERIPH to MEM
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0x3: reserved for PERIPH to PERIPH
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-bit 9 : Peripheral Increment Address
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0x0: no address increment between transfers
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0x1: increment address between transfers
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-bit 10 : Memory Increment Address
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0x0: no address increment between transfers
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0x1: increment address between transfers
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-bit 11-12 : Peripheral data size
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0x0: Byte (8 bits)
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0x1: Half-word (16 bits)
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0x2: Word (32 bits)
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0x3: reserved
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-bit 13-14 : Memory data size
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0x0: Byte (8 bits)
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0x1: Half-word (16 bits)
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0x2: Word (32 bits)
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0x3: reserved
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-bit 15: Peripheral Increment Offset Size not USED for DMA V2
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0x0: offset size is linked to the peripheral bus width
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0x1: offset size is fixed to 4 (32-bit alignment)
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-bit 16-17 : Priority level
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0x0: low
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0x1: medium
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0x2: high
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0x3: very high
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example for stm32wb55x
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dmamux1: dmamux@40020800 {
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compatible = "st,stm32-dmamux";
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...
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dma-channels = <14>;
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dma-generators = <4>;
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dma-requests= <36>;
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status = "disabled";
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};
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for client SPI of stm32wb55x
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spi1: spi@40013000 {
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compatible = "st,stm32-spi";
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dmas = <&dmamux1 11 7 0x20440
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&dmamux1 1 6 0x20480>;
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dma-names = "tx", "rx";
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};
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compatible: "st,stm32-dmamux"
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include: dmamux-controller.yaml
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properties:
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reg:
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required: true
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"#dma-cells":
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const: 3
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# Parameter syntax of stm32 follows the dma client dts syntax
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# in the Linux kernel declared in
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# https://git.kernel.org/pub/scm/linux/kernel/git/devicetree/devicetree-rebasing.git/plain/Bindings/dma/st,stm32-dmamux.yaml
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dma-cells:
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- channel
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- slot
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- channel-config
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